Optical component and timepiece

ABSTRACT

An optical component includes a base material and a film containing silica particles and conductive transparent metal oxide particles. The conductive transparent metal oxide particles are preferably composed of SnO 2 . The number-based average particle diameter of the conductive transparent metal oxide particles is preferably 0.8 nm or more and 5.0 nm or less. When the content of the silica particles in the film is represented by Xs (vol %) and the content of the conductive transparent metal oxide particles in the film is represented by Xc (vol %), it is preferred to satisfy the following relationship: 0.003≦Xc/Xs≦0.12.

BACKGROUND

1. Technical Field

The present invention relates to an optical component and a timepiece.

2. Related Art

In an optical component such as a cover glass for a timepiece, amaterial having high transparency such as any of various glass materialsand various plastic materials is generally used.

On such an optical component, for example, a film such as anantireflection film for the purpose of preventing undesirable lightreflection is sometimes provided (see, for example, JP-A-2010-37115).

However, in the related art, adhesion of dirt due to static electricityor the like cannot be effectively prevented while ensuring the lighttransmittance of the optical component.

SUMMARY

An advantage of some aspects of the invention is to provide an opticalcomponent having an excellent antistatic function while havingsufficient light transmittance, and also to provide a timepieceincluding an optical component having an excellent antistatic functionwhile having sufficient light transmittance.

An optical component according to an aspect of the invention includes abase material and a film containing silica particles and conductivetransparent metal oxide particles.

According to this configuration, an optical component having anexcellent antistatic function while having sufficient lighttransmittance can be provided.

In the optical component according to the aspect of the invention, it ispreferred that the volume resistivity of the constituent material of theconductive transparent metal oxide particles is 100 Ωcm or less.

According to this configuration, the antistatic property of the opticalcomponent can be made particularly excellent.

In the optical component according to the aspect of the invention, it ispreferred that the conductive transparent metal oxide particles arecomposed of SnO₂.

SnO₂ not only has high transparency, but also has a relatively lowrefractive index, and therefore, has a few effects on the antireflectionproperty. Further, SnO₂ is relatively inexpensive and can be easily andstably obtained.

In the optical component according to the aspect of the invention, it ispreferred that the number-based average particle diameter of theconductive transparent metal oxide particles is 0.8 nm or more and 5.0nm or less.

According to this configuration, the antistatic function can be madeparticularly excellent while making the transparency of the filmparticularly excellent. Further, the film can be made relatively dense,and the strength of the film and the durability of the optical componentcan be made particularly excellent.

In the optical component according to the aspect of the invention, it ispreferred that the number-based average particle diameter of the silicaparticles is 0.5 nm or more and 4.0 nm or less.

According to this configuration, a mixing state of the silica particlesand the conductive transparent metal oxide particles in the film can bemade favorable, and the antistatic function of the optical component canbe made particularly excellent. Further, the film can be made relativelydense, and the strength of the film and the durability of the opticalcomponent can be made particularly excellent. In addition, theantireflection function and the like of the film can also be madeparticularly excellent.

In the optical component according to the aspect of the invention, whenthe number-based average particle diameter of the silica particles isrepresented by Ds (nm) and the number-based average particle diameter ofthe conductive transparent metal oxide particles is represented by Dc(nm), it is preferred to satisfy the following relationship:0.1≦Dc/Ds≦0.6.

According to this configuration, a mixing state of the silica particlesand the conductive transparent metal oxide particles in the film can bemade more favorable, and the antistatic function of the opticalcomponent can be made particularly excellent. Further, the film can bemade relatively dense, and the strength of the film and the durabilityof the optical component can be made particularly excellent. Inaddition, the antireflection function and the like of the film can alsobe made particularly excellent.

In the optical component according to the aspect of the invention, whenthe content of the silica particles in the film is represented by Xs(vol %) and the content of the conductive transparent metal oxideparticles in the film is represented by Xc (vol %), it is preferred tosatisfy the following relationship: 0.003≦Xc/Xs≦0.12.

According to this configuration, the antistatic function can be madeparticularly excellent while making the antireflection function and thelike of the film excellent. Further, the film can be made relativelydense, and the strength of the film and the durability of the opticalcomponent can be made particularly excellent. In addition, thetransparency of the film can be made particularly excellent.

In the optical component according to the aspect of the invention, it ispreferred that the thickness of the film is 50 nm or more and 120 nm orless.

According to this configuration, the durability, antistatic function,and the like of the optical component can be made particularlyexcellent.

In the optical component according to the aspect of the invention, it ispreferred that the base material is composed of a material containing atleast one member selected from the group consisting of a silicate glass,a sapphire glass, and a plastic.

These materials have excellent transparency, and therefore, the opticalproperty of the optical component can be made particularly excellent.Further, in the case where a film is provided on a base materialcomposed of such a material, the antireflection function is moreeffectively exhibited.

In the optical component according to the aspect of the invention, it ispreferred that the optical component is a cover glass for a timepiece.

Time-displaying members such as a dial plate and hands are generallydisposed on a rear surface side of the cover glass, and therefore, thecover glass (optical component) is a member which is strongly requiredto have visibility of a dial plate and the like through the cover glass(optical component). Therefore, the cover glass is a member in which aproblem of decreasing the visibility particularly remarkably occurs whendirt such as dust adheres to the cover glass due to static electricity.Further, in the case where the cover glass is undesirably charged withelectricity, due to the effect, the hands such as an hour hand may bedeformed, and therefore, a breakdown or the like of the timepiece may becaused due to such deformation. On the other hand, in the case where theinvention is applied to a cover glass for a timepiece, the occurrence ofthe problem as described above can be effectively prevented. Therefore,by applying the invention to a cover glass for a timepiece, the effectof the invention is more remarkably exhibited.

Further, in the optical component according to the aspect of theinvention, also an excellent antireflection function is exhibited, andtherefore, the visibility of the time-displaying members such as a dialplate and hands disposed on the rear surface side of the cover glass canbe made particularly excellent.

A timepiece according to an aspect of the invention includes the opticalcomponent according to the aspect of the invention.

According to this configuration, a timepiece including the opticalcomponent having an excellent antistatic function while havingsufficient light transmittance can be provided.

According to the aspects of the invention, an optical component havingan excellent antistatic function while having sufficient lighttransmittance can be provided, and also a timepiece including theoptical component having an excellent antistatic function while havingsufficient light transmittance can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described with reference to the accompanyingdrawings, wherein like numbers reference like elements.

FIG. 1 is a cross-sectional view schematically showing a firstembodiment of an optical component according to the invention.

FIG. 2 is a view schematically showing one example of a particle sizedistribution of silica particles constituting a film of an opticalcomponent according to the invention.

FIG. 3 is a cross-sectional view schematically showing a secondembodiment of an optical component according to the invention.

FIG. 4 is a partial cross-sectional view showing a preferred embodimentof a timepiece (wristwatch) according to the invention.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Hereinafter, preferred embodiments of the invention will be described indetail with reference to the accompanying drawings.

Optical Component

First, an optical component according to the invention will bedescribed.

First Embodiment

FIG. 1 is a cross-sectional view schematically showing a firstembodiment of an optical component according to the invention, and FIG.2 is a view schematically showing one example of a particle sizedistribution of silica particles constituting a film of an opticalcomponent according to the invention.

As shown in FIG. 1, an optical component P10 of this embodiment includesa base material P1 and a film P2 containing silica particles P21 andconductive transparent metal oxide particles P22.

According to such a configuration, the optical component P10 exhibits anantistatic function as a whole. In other words, the film P2 can functionas an antistatic film. As a result, for example, the adhesion of dirtsuch as dust due to static electricity can be prevented, and thus, theoptical component P10 can stably exhibit the inherent optical property.

The silica particles P21 and the conductive transparent metal oxideparticles P22 are both a material with transparency, and therefore, thetransparency and light transmittance of the optical component P10 as awhole can be made sufficiently excellent. Accordingly, the opticalproperty of the optical component P10 can be made sufficientlyexcellent.

Such an excellent effect is obtained by using the silica particles P21and the conductive transparent metal oxide particles P22 in combination,and the excellent effect as described above is not obtained by aconfiguration devoid of either one of these components. That is, in thecase where a configuration in which the conductive transparent metaloxide particles are not contained in a film composed of a materialcontaining the silica particles is adopted, a sufficient antistaticfunction is not obtained. Further, in the case where another conductivematerial is contained in place of the conductive transparent metal oxideparticles in a film composed of a material containing the silicaparticles, when a sufficient antistatic function is tried to beobtained, for example, the transparency of the film is decreased, andtherefore, a problem occurs such that the optical property of theoptical component is significantly deteriorated, the durability of thefilm is significantly deteriorated, or the like. Further, in the casewhere a configuration in which the silica particles are not contained ina film composed of a material containing the conductive transparentmetal oxide particles is adopted, for example, the transparency of thefilm is decreased, and therefore, the optical property of the opticalcomponent is significantly deteriorated.

Further, by including the film P2 containing the silica particles P21and the conductive transparent metal oxide particles P22, for example,by using silica particles having a given particle size distribution asthe silica particles P21, a particularly excellent antireflectionfunction is obtained. In other words, the film P2 can function as anantireflection film. In addition, an excellent antireflection functionis obtained with a very simple structure as compared with anantireflection film in the related art.

The reason why such an excellent antireflection function is obtained isconsidered to be because by including the silica particles P21 and theconductive transparent metal oxide particles P22, a favorable opticalinterference effect is exhibited.

Further, by including the film P2 containing the silica particles P21and the conductive transparent metal oxide particles P22, the opticalcomponent P10 has an excellent antifogging property. As a result, adecrease in the optical property due to dew condensation or the like canbe reliably prevented.

The reason why such an excellent antifogging property is obtained isconsidered to be because by including the silica particles P21 and theconductive transparent metal oxide particles P22, a fine fractalstructure is favorably formed.

Further, in the related art, an optical component is sometimes used byproviding a resin film on an optical component main body (basematerial). However, such a resin film has a problem that the abrasionresistance is low, and for example, when dirt adheres to the surface ofthe optical component, a wiping operation cannot be performed, and thelike. On the other hand, the film P2 as described above also hasexcellent abrasion resistance, and therefore, a wiping operation canalso be favorably performed.

Such a film P2 can be more easily formed by, for example, a coatingmethod or the like as described in detail later.

Due to this, the optical component P10 having an excellent antistaticfunction and the like can be obtained with high productivity withoutusing a large and expensive apparatus. Further, the production cost ofthe optical component P10 can also be decreased.

Base Material

The base material P1 constitutes a main part of the optical componentP10 and is generally a member which has light transmittance.

The refractive index of the base material P1 for a light with awavelength of 589 nm is preferably 1.43 or more and 1.85 or less, morepreferably 1.45 or more and 1.78 or less.

According to this, the optical property of the optical component P10 canbe made particularly excellent.

The constituent material of the base material P1 is not particularlylimited, and for example, various glasses, various plastics, and thelike can be used. However, it is preferably a material containing atleast one member selected from the group consisting of a silicate glass(a quartz glass or the like), a sapphire glass, and a plastic.

These materials have excellent transparency. Further, in the case wherethe film P2 is provided on the base material P1 composed of such amaterial, the antireflection function attributed to the film P2 is moreeffectively exhibited.

In particular, in the case where the base material P1 contains at leastone of a silicate glass and a sapphire glass, excellent opticalproperties such as particularly excellent light transmittance and amoderate refractive index are obtained, and also the adhesivenessthereof to the film P2 is made particularly excellent, and thus, thedurability of the optical component P10 as a whole can be madeparticularly excellent.

Examples of a plastic material constituting the base material P1 includevarious thermoplastic resins and various thermosetting resins, andspecific examples thereof include polyolefins such as polyethylene,polypropylene, ethylene-propylene copolymers, and ethylene-vinyl acetatecopolymers (EVA), cyclic polyolefins (COP), modified polyolefins,polyvinyl chloride, polyvinylidene chloride, polystyrene, polyamides(for example, nylon 6, nylon 46, nylon 66, nylon 610, nylon 612, nylon11, nylon 12, nylon 6-12, and nylon 6-66),polyimides,polyamideimides,polycarbonate (PC), poly-(4-methylpentene-1),ionomers, acrylic resins, polymethyl methacrylate,acrylonitrile-butadiene-styrene copolymers (ABS resins),acrylonitrile-styrene copolymers (AS resins), butadiene-styrenecopolymers, polyoxymethylene, polyvinyl alcohol (PVA), ethylene-vinylalcohol copolymers (EVOH), polyesters such as polyethylene terephthalate(PET), polybutylene terephthalate (PBT), and polycyclohexaneterephthalate (PCT), polyether, polyether ketone (PEK), polyether etherketone (PEEK), polyether imide, polyacetal (POM), polyphenylene oxide,modified polyphenylene oxide, polysulfone, polyether sulfone,polyphenylene sulfide, polyarylate, aromatic polyesters (liquid crystalpolymers), polytetrafluoroethylene, polyvinylidene fluoride, otherfluororesins, various thermoplastic elastomers such as styrene-based,polyolefin-based, polyvinyl chloride-based, polyurethane-based,polyester-based, polyamide-based, polybutadiene-based,trans-polyisoprene-based, fluororubber-based, and chlorinatedpolyethylene-based elastomers, epoxy resins, phenolic resins, urearesins, melamine resins, unsaturated polyesters, silicone-based resins,urethane-based resins, poly-para-xylylene resins such aspoly-para-xylylene, poly-monochloro-para-xylylene,poly-dichloro-para-xylylene, poly-monofluoro-para-xylylene, andpoly-monoethyl-para-xylylene, and also include copolymers, blends, andpolymer alloys composed mainly of these materials. Among these, one typeor two or more types in combination (for example, as a blend resin, apolymer alloy, a stacked body, or the like) can be used.

Film

The film P2 is composed of a material containing silica particles P21and conductive transparent metal oxide particles P22.

Silica Particles

The number-based average particle diameter of the silica particles P21constituting the film P2 is not particularly limited, but is preferably0.5 nm or more and 4.0 nm or less, more preferably 1.0 nm or more and2.0 nm or less.

According to this, a mixing state of the silica particles P21 and theconductive transparent metal oxide particles P22 in the film P2 can bemade favorable, and the antistatic function of the optical component P10can be made particularly excellent. Further, the film P2 can be maderelatively dense, and the strength of the film P2 and the durability ofthe optical component P10 can be made particularly excellent. Inaddition, the antireflection function and the like of the film P2 canalso be made particularly excellent.

As shown in FIG. 2, it is preferred that the silica particles P21contained in the film P2 have a first local maximum MV1 in the range of1.5 nm or more and 2.5 nm or less (a first range R1), a second localmaximum MV2 in the range of 3.5 nm or more and 4.5 nm or less (a secondrange R2), and a third local maximum MV3 in the range of 7.5 nm or moreand 8.5 nm or less (a third range R3) in a number-based particle sizedistribution.

Because of having such a particle size distribution, a particularlyexcellent antireflection function is obtained.

The reason why such an excellent antireflection function is obtained isconsidered to be because by including the silica particles P21 having aparticle size distribution as described above, a more favorable opticalinterference effect is exhibited.

Further, by including the silica particles P21 having a particle sizedistribution as described above, the optical component P10 has also aparticularly excellent antifogging property.

The reason why such an excellent antifogging property is obtained isconsidered to be because by including the silica particles P21 having aparticle size distribution as described above, a fine fractal structureis more favorably formed.

Further, the density (the filling ratio of the silica particles P21) ofthe film P2 can be made high, and thus, the strength of the film P2 andthe durability of the optical component P10 can be made excellent.

The ratio of the silica particles P21 having a particle diameter of 1.5nm or more and 2.5 nm or less (the ratio of the silica particles P21falling within the first range R1) to the sum of the volumes of thesilica particles P21 constituting the film P2 is preferably 5% by volumeor more and 30% by volume or less, more preferably 10% by volume or moreand 25% by volume or less.

According to this, the film P2 can be made relatively dense while makingthe antireflection function and the like of the film P2 particularlyexcellent, and the strength of the film P2 and the durability of theoptical component P10 can be made particularly excellent.

The ratio of the silica particles P21 having a particle diameter of 3.5nm or more and 4.5 nm or less (the ratio of the silica particles P21falling within the second range R2) to the sum of the volumes of thesilica particles P21 constituting the film P2 is preferably 10% byvolume or more and 40% by volume or less, more preferably 15% by volumeor more and 35% by volume or less.

According to this, the film P2 can be made relatively dense while makingthe antireflection function and the like of the film P2 particularlyexcellent, and the strength of the film P2 and the durability of theoptical component P10 can be made particularly excellent.

The ratio of the silica particles P21 having a particle diameter of 7.5nm or more and 8.5 nm or less (the ratio of the silica particles P21falling within the third range R3) to the sum of the volumes of thesilica particles P21 constituting the film P2 is preferably 30% byvolume or more and 60% by volume or less, more preferably 35% by volumeor more and 55% by volume or less.

According to this, the film P2 can be made relatively dense while makingthe antireflection function and the like of the film P2 particularlyexcellent, and the strength of the film P2 and the durability of theoptical component P10 can be made particularly excellent.

In the number-based particle size distribution, the range of theparticle diameter in which the first local maximum MV1 is present may be1.5 nm or more and 2.5 nm or less, but is preferably 1.6 nm or more and2.4 nm or less, and more preferably 1.8 nm or more and 2.2 nm or less.

According to this, the antireflection function and the like of the filmP2 can be made particularly excellent.

In the number-based particle size distribution, the range of theparticle diameter in which the second local maximum MV2 is present maybe 3.5 nm or more and 4.5 nm or less, but is preferably 3.6 nm or moreand 4.4 nm or less, and more preferably 3.8 nm or more and 4.2 nm orless.

According to this, the antireflection function and the like of the filmP2 can be made particularly excellent.

In the number-based particle size distribution, the range of theparticle diameter in which the third local maximum MV3 is present may be7.5 nm or more and 8.5 nm or less, but is preferably 7.6 nm or more and8.4 nm or less, and more preferably 7.8 nm or more and 8.2 nm or less.

According to this, the antireflection function and the like of the filmP2 can be made particularly excellent.

It is preferred that the silica particles P21 further have a fourthlocal maximum MV4 in the range of 5.5 nm or more and 6.5 nm or less (afourth range R4) in addition to the above-mentioned first local maximumMV1, second local maximum MV2, and third local maximum MV3 in thenumber-based particle size distribution.

According to this, the antireflection function and the like of the filmP2 can be made particularly excellent.

The ratio of the silica particles P21 having a particle diameter of 5.5nm or more and 6.5 nm or less (the ratio of the silica particles P21falling within the fourth range R4) to the sum of the volumes of thesilica particles P21 constituting the film P2 is preferably 20% byvolume or more and 30% by volume or less, more preferably 22% by volumeor more and 28% by volume or less.

According to this, the film P2 can be made relatively dense while makingthe antireflection function and the like of the film P2 particularlyexcellent, and the strength of the film P2 and the durability of theoptical component P10 can be made particularly excellent.

In the number-based particle size distribution, the range of theparticle diameter in which the fourth local maximum MV4 is present maybe 5.5 nm or more and 6.5 nm or less, but is preferably 5.6 nm or moreand 6.4 nm or less, and more preferably 5.8 nm or more and 6.2 nm orless.

According to this, the antireflection function and the like of the filmP2 can be made particularly excellent.

The measurement of the particle size distribution can be performed byusing various methods, for example, a dynamic light scattering method, alaser diffraction method, an image analysis method, a gravitysedimentation method, and the like, but is preferably performed by usinga laser diffraction method.

According to this, the particle size distribution can be obtained moreeasily. Further, in either case of a dry process or a wet process, themeasurement can be favorably performed, and a relatively large amount ofa sample can be treated at a time.

Examples of an apparatus which can be used for measuring the particlesize distribution include a single nanoparticle size analyzer (IG-1000)manufactured by Shimadzu Corporation.

The content of the silica particles P21 in the film P2 (the contentthereof to the total solid components) is preferably 90% by volume ormore and 99.5% by volume or less, further more preferably 92% by volumeor more and 99% by volume or less.

According to this, the antistatic function, antireflection function, andthe like can be made particularly excellent while making thetransparency of the film P2 particularly excellent.

Conductive Transparent Metal Oxide Particles

The film P2 contains conductive transparent metal oxide particles P22composed of a metal oxide with electrical conductivity and transparency.

By including such conductive transparent metal oxide particles P22 alongwith the silica particles P21, an antistatic function and the like canbe imparted while making the optical property of the optical componentP10 excellent.

In general, a metal oxide (particularly, a conductive metal oxide) hasexcellent chemical stability, and undesirable denaturation or the likethereof hardly occurs in the film P2. Therefore, the function asdescribed above can be exhibited stably over a long period of time.

The conductive transparent metal oxide particles P22 constituting thefilm P2 may be any as long as it is composed of a transparent metaloxide with electrical conductivity, however, the volume resistivity ofthe constituent material of the conductive transparent metal oxideparticles P22 is preferably 100 Ωcm or less.

According to this, the antistatic property of the optical component P10can be made particularly excellent.

Examples of the metal oxide (transparent metal oxide) constituting theconductive transparent metal oxide particles P22 include In₂O₃, ZnO,CdO, Ga₂O₃, and SnO₂, materials obtained by doping any of theabove-mentioned compounds with tin (Sn), antimony (Sb), aluminum (Al),gallium (Ga), or the like (for example, ITO (Sn-doped In₂O₃), AZO(Al-doped ZnO), GZO (Ga-doped ZnO), and the like), and materialscontaining two or more compounds selected therefrom (for example, IZO(In₂O₃—ZnO), IGZO (In₂O₃—Ga₂O₃—ZnO), and the like).

Above all, as the constituent material of the conductive transparentmetal oxide particles P22, SnO₂ is preferred. SnO₂ not only has hightransparency, but also has a relatively low refractive index, andtherefore, has a few effects on the antireflection property. Further,SnO₂ is relatively inexpensive, and SnO₂ particles having a particlediameter as described later can be easily and stably obtained.

The number-based average particle diameter of the conductive transparentmetal oxide particles P22 is not particularly limited, but is preferably0.8 nm or more and 5.0 nm or less, more preferably 1.0 nm or more and3.0 nm or less, further more preferably 1.3 nm or more and 2.7 nm orless.

According to this, the antistatic function can be made particularlyexcellent while making the transparency of the film P2 particularlyexcellent. Further, the film P2 can be made relatively dense, and thestrength of the film P2 and the durability of the optical component P10can be made particularly excellent.

When the number-based average particle diameter of the silica particlesP21 is represented by Ds (nm) and the number-based average particlediameter of the conductive transparent metal oxide particles P22 isrepresented by Dc (nm), it is preferred to satisfy the followingrelationship: 0.1≦Dc/Ds≦0.6, it is more preferred to satisfy thefollowing relationship: 0.2≦Dc/Ds≦0.5, and it is further more preferredto satisfy the following relationship: 0.3≦Dc/Ds≦0.4.

By satisfying such a relationship, a mixing state of the silicaparticles P21 and the conductive transparent metal oxide particles P22in the film P2 can be made more favorable, and the antistatic functionof the optical component P10 can be made particularly excellent.Further, the film P2 can be made relatively dense, and the strength ofthe film P2 and the durability of the optical component P10 can be madeparticularly excellent. In addition, the antireflection function and thelike of the film P2 can also be made particularly excellent.

The content of the conductive transparent metal oxide particles P22 inthe film P2 (the content thereof to the total solid components) ispreferably 0.5% by volume or more and 10% by volume or less, morepreferably 1.0% by volume or more and 8.0% by volume or less.

According to this, the antistatic function can be made particularlyexcellent while making the antireflection function and the like of thefilm P2 excellent.

When the content of the silica particles P21 in the film P2 (the contentthereof to the total solid components) is represented by Xs (vol %) andthe content of the conductive transparent metal oxide particles P22 inthe film P2 (the content thereof to the total solid components) isrepresented by Xc (vol %), it is preferred to satisfy the followingrelationship: 0.003≦Xc/Xs≦0.12, and it is more preferred to satisfy thefollowing relationship: 0.005≦Xc/Xs≦0.1.

According to this, the antistatic function can be made particularlyexcellent while making the antireflection function and the like of thefilm P2 excellent. Further, the film P2 can be made relatively dense,and the strength of the film P2 and the durability of the opticalcomponent P10 can be made particularly excellent. Further, thetransparency of the film P2 can be made particularly excellent.

Another Component

The film P2 may contain a component other than the above-mentionedcomponents.

Examples of such a component include an antifungal agent, apreservative, an antioxidant, an ultraviolet absorber, a binder, and aslipping agent (leveling agent).

The porosity of the film P2 is preferably 15% by volume or more and 36%by volume or less, more preferably 18% by volume or more and 32% byvolume or less.

According to this, while making the durability of the optical componentP10 as a whole sufficiently excellent, the refractive index of the filmP2 as a whole can be more easily adjusted so as to fall within apreferred range, and the antireflection function can be madeparticularly excellent. Further, the antistatic function attributed tothe film P2 can be made particularly excellent.

The porosity of the film P2 refers to the ratio of pores accounting forthe entire volume of the film P2, and the pore encompasses not only aspace provided among particles constituting the film P2, but also a holeprovided inside the particle.

The surface roughness Ra of the film P2 is preferably 0.5 nm or more and10.0 nm or less, more preferably 0.7 nm or more and 6.0 nm or less.

According to this, the antifogging property of the optical component P10can be made particularly excellent while making the light transmittanceof the optical component P10 as a whole sufficiently excellent.

The thickness of the film P2 is preferably 50 nm or more and 120 nm orless, more preferably 60 nm or more and 100 nm or less.

According to this, the durability, antistatic function, and the like ofthe optical component P10 can be made particularly excellent whileeffectively preventing the optical property of the optical component P10from being adversely affected.

Examples of the optical component include various lenses (includingmicrolenses, lenticular lenses, fresnel lenses, and the like) such asprojector lenses, camera lenses, and eyeglass lenses, filters (cameralow-pass filters, and the like), light transmitting plates, dust-proofglasses, radiator plates, cover glasses for timepieces, rear lids fortimepieces, and light transmitting dial plates (for example, dial platesfor solar timepieces).

Among these, the optical component is preferably a cover glass for atimepiece.

Time-displaying members such as a dial plate and hands are generallydisposed on a rear surface side of the cover glass, and therefore, thecover glass (optical component) is a member which is strongly requiredto have visibility of a dial plate and the like through the cover glass(optical component). Therefore, the cover glass is a member in which aproblem of decreasing the visibility particularly remarkably occurs whendirt such as dust adheres to the cover glass due to static electricity.Further, in the case where the cover glass is undesirably charged withelectricity, due to the effect, the hands such as an hour hand may bedeformed, and therefore, a breakdown or the like of the timepiece may becaused due to such deformation. On the other hand, in the case where theinvention is applied to a cover glass for a timepiece, the occurrence ofthe problem as described above can be effectively prevented. Therefore,by applying the invention to a cover glass for a timepiece, the effectof the invention is more remarkably exhibited.

Further, in the optical component according to the invention, anexcellent antireflection function is also exhibited, and therefore, thevisibility of the time-displaying members such as a dial plate and handsdisposed on the rear surface side of the cover glass can be madeparticularly excellent.

In the case of a diver's watch or the like, the visibility through thecover glass sometimes largely affects the safety of an observer (user),however, according to the invention, an antireflection function is alsoexhibited, and therefore, also in an optical component for a timepieceto be used in such a severe environment, the effect as described abovecan be reliably exhibited.

Further, in a diver's watch or the like, liquid tightness in a case ismaintained, however, a humidity contained in the case when assemblingthe watch is dew-condensed during use to cause a problem of decreasingthe visibility in some cases. However, according to the invention, theoptical component also has a high antifogging property, and therefore,for example, in a diver's watch, by disposing a cover glass (opticalcomponent), to which the invention is applied, such that a surfaceprovided with the film faces the inner surface side, the problem of dewcondensation as described above can be more reliably prevented.

Second Embodiment

FIG. 3 is a cross-sectional view schematically showing a secondembodiment of the optical component according to the invention. In thefollowing description, different points from the above embodiment willbe mainly described, and the description of the same matter will beomitted.

As shown in FIG. 3, an optical component P10 of this embodiment includesa base material P1, a film P2 containing silica particles P21 andconductive transparent metal oxide particles P22, and a foundation layerP3.

In this manner, by including the foundation layer P3, for example, theadhesiveness between the base material P1 and the film P2 (theadhesiveness through the foundation layer P3) can be made particularlyexcellent, and thus, the durability and reliability of the opticalcomponent P10 can be made particularly excellent.

Examples of a constituent material of the foundation layer P3 includevarious resin materials and SiO₂.

The thickness of the foundation layer P3 is not particularly limited,but is preferably 5 nm or more and 25 nm or less, more preferably 10 nmor more and 20 nm or less.

In the configuration shown in the drawing, only one foundation layer P3is formed, however, the optical component P10 may include a plurality offoundation layers between the base material P1 and the film P2.

Method for Producing Optical Component

Next, a method for producing the optical component will be described.

The optical component P10 may be produced by any method, but can befavorably produced by, for example, using a method including a basematerial preparation step (1a) of preparing a base material P1, a filmforming composition application step (1b) of applying a film formingcomposition containing silica particles P21, conductive transparentmetal oxide particles P22, and a dispersion medium onto the basematerial P1, and a dispersion medium removal step (1c) of removing thedispersion medium from the film forming composition applied onto thebase material P1.

Base Material Preparation Step

In this step, a base material P1 is prepared (1a).

As the base material P1, a material described above can be used,however, a material subjected to a pretreatment such as a washingtreatment or a lyophilization treatment may be used. Further, as thepretreatment, a mask may be formed in a region where the film P2 is notdesired to be formed. In this case, as a post-treatment step, a maskremoval step may be included.

Film Forming Composition Application Step

In this step, a film forming composition containing silica particlesP21, conductive transparent metal oxide particles P22, and a dispersionmedium for dispersing these particles is applied onto the base materialP1 (1b).

Such a film forming composition contains a dispersion medium and hasexcellent fluidity, and therefore, the film P2 in which an undesirablevariation in the thickness is more effectively prevented can be easilyand reliably formed.

Examples of the method for applying the film forming composition ontothe base material P1 include various printing methods such as an inkjetmethod, various coating methods such as roll coating, spray coating,spin coating, and brush coating, and dipping (a dipping method).

The dispersion medium constituting the film forming composition may beany as long as it has a function to disperse the silica particles P21and the conductive transparent metal oxide particles P22, however,examples thereof include water; alcohol-based solvents such as methanol,ethanol, isopropanol, ethylene glycol, propylene glycol, and glycerin;ketone-based solvents such as methyl ethyl ketone and acetone; glycolether-based solvents such as ethylene glycol monoethyl ether andethylene glycol monobutyl ether; glycol ether acetate-based solventssuch as propylene glycol 1-monomethyl ether 2-acetate and propyleneglycol 1-monoethyl ether 2-acetate; polyethylene glycol andpolypropylene glycol, and one type or a combination of two or more typesselected from these solvents can be used.

Among these, as the dispersion medium, water, an alcohol-based solvent,or a glycol-based solvent (in addition to a glycol such as ethyleneglycol or propylene glycol, a compound such as an ether, an ester, orthe like of a glycol such as a glycol ether-based solvent or a glycolether acetate-based solvent) is preferred.

According to this, the dispersion stability of the silica particles P21and the conductive transparent metal oxide particles P22 in the filmforming composition can be made particularly excellent, and theoccurrence of an undesirable variation in the composition in the film P2to be formed and an undesirable variation in the thickness thereof canbe more effectively prevented.

In particular, in the case where the film forming composition is appliedby a method such as roll coating or spin coating, it is preferred to usewater or an alcohol-based solvent as the dispersion medium.

According to this, the coatability of the film forming composition onthe base material P1 can be made particularly excellent.

In the case where the film forming composition is applied by a methodsuch as spray coating, it is preferred to use a glycol-based solvent asthe dispersion medium.

According to this, the coatability of the film forming composition ontothe base material P1 can be made particularly excellent. Further,clogging can be prevented, and thus, the productivity and the like ofthe optical component P10 can be made particularly high.

The film forming composition may contain a component (another component)other than the silica particles P21, the conductive transparent metaloxide particles P22, and the dispersion medium. Examples of such acomponent (another component) include an antifungal agent, apreservative, an antioxidant, an ultraviolet absorber, a binder, and aslipping agent (leveling agent).

The content of the silica particles P21 in the film forming compositionis not particularly limited, but is preferably 0.5% by mass or more and10% by mass or less.

According to this, the fluidity of the film forming composition can bemade favorable, and the occurrence of an undesirable variation in thethickness or the like in the film P2 to be formed can be moreeffectively prevented, and also the efficiency of forming the film P2can be made particularly excellent, and thus, the productivity of theoptical component P10 can be made particularly high.

The content of the conductive transparent metal oxide particles P22 inthe film forming composition is not particularly limited, but ispreferably 0.02% by mass or more and 0.5% by mass or less.

According to this, the fluidity of the film forming composition can bemade favorable, and the occurrence of an undesirable variation in thethickness or the like in the film P2 to be formed can be moreeffectively prevented, and also the efficiency of forming the film P2can be made particularly excellent, and thus, the productivity of theoptical component P10 can be made particularly high.

The content of the dispersion medium in the film forming composition isnot particularly limited, but is preferably 90% by mass or more and99.5% by mass or less.

According to this, the fluidity of the film forming composition can bemade favorable, and the occurrence of an undesirable variation in thethickness or the like in the film P2 to be formed can be moreeffectively prevented, and also the efficiency of forming the film P2can be made particularly excellent, and thus, the productivity of theoptical component P10 can be made particularly high.

The viscosity of the film forming composition in this step as measuredaccording to JIS Z 8809 using a vibration-type viscometer is preferably20 mPa·s or less, more preferably 3 mPa·s or more and 15 mPa·s or less.

According to this, the application of the film forming composition ontothe base material P1 can be favorably performed, and the occurrence ofan undesirable variation in the thickness or the like in the film P2 tobe formed can be more effectively prevented, and also the efficiency offorming the film P2 can be made particularly excellent, and thus, theproductivity of the optical component P10 can be made particularly high.

Dispersion Medium Removal Step

In this step, the dispersion medium is removed from the film formingcomposition applied onto the base material P1 (1c).

According to this, the film P2 strongly bonded to the base material P1is formed. In particular, the film forming composition containsparticles (silica particles P21 and conductive transparent metal oxideparticles P22) as constituent components of the film P2.

Due to this, when the dispersion medium is removed in this step, theoccurrence of a phenomenon that the dispersion medium is undesirablyenclosed in the film P2 to be formed so that the dispersion mediumundesirably remains in the optical component P10 to be finally obtainedcan be reliably prevented. As a result, the optical property andreliability of the optical component P10 can be reliably made excellent.Further, since the film forming composition contains particles (silicaparticles P21 and conductive transparent metal oxide particles P22) asconstituent components of the film P2, the dispersion medium containedin the film forming composition in the form of a film can be maintainedin a state where it communicates with the outside constantly in thisstep, and therefore, the dispersion medium can be efficiently removedfrom the film forming composition in the form of a film. As a result,the productivity of the optical component P10 can be made high.

This step can be performed by, for example, a heating treatment, avacuum treatment, an air blowing treatment, or the like, and two or moretreatments selected therefrom may be performed in combination.

In the case where this step is performed by a heating treatment, theheating temperature is preferably 50° C. or higher and 200° C. or lower,more preferably 60° C. or higher and 180° C. or lower. Further, theheating temperature in this step is preferably lower than the boilingpoint of the dispersion medium of the film forming composition.

According to this, the film P2 can be efficiently formed whilepreventing undesirable deterioration, denaturation, or the like of thematerial, or undesirable deformation or the like of the film P2 or thelike.

In the case where this step is performed by a vacuum treatment, thepressure during the vacuum treatment (the pressure of the environment inwhich the base material P1 having the film forming composition appliedthereon is placed) is preferably 1×10² Pa or less, more preferably 1×10¹Pa or less.

According to this, the productivity of the optical component P10 can bemade particularly high. Further, the occurrence of an adverse effectcaused by the dispersion medium remaining in the finally obtainedoptical component P10 can be more reliably prevented.

In this step, for example, two or more treatments under differentconditions may be performed.

For example, a first heating treatment which is performed at arelatively low temperature and a second heating treatment which isperformed at a higher temperature than in the first heating treatmentmay be performed. According to this, while more effectively preventingthe occurrence of a defect (for example, the occurrence of a relativelylarge pore, undesirable deformation of the film P2, or the like) or thelike in the film P2 to be formed, the efficiency of forming the film P2can be made particularly excellent.

The film forming composition application step and the dispersion mediumremoval step may be performed repeatedly. According to this, even a filmhaving a relatively large thickness can be favorable formed. Inaddition, the film P2 can be favorably formed at a plurality of placeson the base material P1. For example, even in the case where the film P2is formed at a plurality of places where it is difficult to apply thefilm forming composition by performing a single film forming compositionapplication step, or in the case where the films P2 having a differentcondition, for example, having a different thickness are formed, etc.,this production method can be favorably applied.

Further, as shown in FIG. 3, in the case where the optical component P10having the foundation layer P3 between the base material P1 and the filmP2 is produced, for example, by providing a foundation layer formingmaterial application step of applying a foundation layer formingmaterial onto the base material P1 prior to the film forming compositionapplication step, the optical component P10 can be favorably produced.

In the case where the foundation layer P3 containing a resin material isformed, as the foundation layer forming material, a material obtained bydissolving the resin material in a solvent, a liquid compositioncontaining a precursor (for example, a monomer, a dimer, a trimer, anoligomer, a prepolymer, or the like) of the resin material can be used.

In the case where such a material is used, examples of the method forapplying the foundation layer forming material include various printingmethods such as an inkjet method, various coating methods such as rollcoating, spray coating, spin coating, and brush coating, and dipping (adipping method).

Further, in the case where the foundation layer P3 composed of, forexample, SiO₂ is formed, a foundation layer formation step of formingthe foundation layer P3 on the surface of the base material P1 by agas-phase deposition method (for example, a vapor deposition method) maybe provided prior to the film forming composition application step.According to this, the adhesiveness between the base material P1 and thefoundation layer P3 can be made particularly excellent, and also thetransparency of the foundation layer P3 can be made particularly high,and thus, the optical property of the optical component P10 as a wholecan be further enhanced.

According to the production method as described above, an opticalcomponent having an excellent antistatic function while havingsufficient light transmittance can be efficiently produced.

Timepiece

Next, a timepiece according to the invention will be described.

The timepiece according to the invention includes the optical componentaccording to the invention as described above.

According to this, a timepiece including the optical component having anexcellent antistatic function while having sufficient lighttransmittance can be provided, and for example, a timepiece in which theoccurrence of an adverse effect of static electricity is effectivelyprevented can be provided, and thus, the reliability of the timepiece asa whole can be made high. Further, a timepiece capable of favorablyvisually recognizing a state on a rear surface side of the opticalcomponent can be provided, and the aesthetic appearance (aestheticity)of the timepiece as a whole can be made excellent, and thus, the valueas an ornament can be increased. In addition, for example, thevisibility of the time and the like can be improved, and therefore, alsothe function (practicality) as a utility article becomes excellent.

The timepiece according to the invention may be any as long as itincludes the optical component according to the invention as at leastone optical component, and as the other components, known components canbe used, however, hereinafter, one example of the configuration of thetimepiece when the optical component according to the invention isapplied to the cover glass will be representatively described.

FIG. 4 is a partial cross-sectional view showing a preferred embodimentof the timepiece (wristwatch) according to the invention.

As shown in FIG. 4, a wristwatch (portable timepiece) P100 of thisembodiment includes a barrel (case) P82, a rear lid P83, a bezel (frame)P84, and a cover glass (a cover glass for a timepiece) P85. In the caseP82, a dial plate for a timepiece (a dial plate) P7, a solar cell P94,and a movement P81 are housed, and further, hands (indicator hands) notshown in the drawing and the like are also housed.

The cover glass P85 is composed of the optical component according tothe invention as described above.

According to this, the visibility of the dial plate P7, the hands(indicator hands), and the like can be enhanced. Further, the dial plateP7 and the like are members which have a large influence on theappearance of the entire timepiece, however, undesirable lightreflection when the dial plate P7 and the like are visually recognizedis prevented, and therefore, the aesthetic appearance (aestheticity) ofthe timepiece as a whole can be made particularly excellent.

The movement P81 drives the indicator hands by utilizing theelectromotive force of the solar cell P94.

Although not shown in FIG. 4, in the movement P81, for example, anelectric double-layer capacitor which stores the electromotive force ofthe solar cell P94, a lithium ion secondary buttery, a crystaloscillator as a time reference source, a semiconductor integratedcircuit which generates a driving pulse for driving the timepiece basedon the oscillation frequency of the crystal oscillator, a step motor fordriving the indicator hands every second by receiving this drivingpulse, a gear train mechanism for transmitting the movement of the stepmotor to the indicator hands, and the like are included.

Further, the movement P81 includes an antenna for receiving a radio wave(not shown), and has a function to perform time adjustment and the likeusing the received radio wave.

The solar cell P94 has a function to convert light energy intoelectrical energy. The electrical energy converted by the solar cell P94is utilized for driving the movement P81 or the like.

The solar cell P94 has, for example, a PIN structure in which a p-typeimpurity and an n-type impurity are selectively introduced into anon-single crystal silicon thin film, and further, an i-type non-singlecrystal silicon thin film having a low impurity concentration isprovided between a p-type non-single crystal silicon thin film and ann-type non-single crystal silicon thin film.

In the barrel P82, a winding stem pipe P86 is fitted and fixed, and inthis winding stem pipe P86, a shaft P871 of a stem P87 is rotatablyinserted.

The barrel P82 and the bezel P84 are fixed to each other with a plasticpacking P88, and the bezel P84 and the cover glass P85 are fixed to eachother with a plastic packing P89.

In the barrel P82, the rear lid P83 is fitted (or threadedly engaged),and in a joint portion (seal portion) P93 of these members, aring-shaped rubber packing (rear lid packing) P92 is inserted in acompressed state. According to this configuration, the seal portion P93is sealed in a liquid-tight manner, whereby a water-proof function isobtained.

A groove P872 is formed in a middle part on an outer periphery of theshaft P871 of the stem P87, and in this groove P872, a ring-shapedrubber packing (stem packing) P91 is fitted. The rubber packing P91 isin close contact with the inner peripheral surface of the winding stempipe P86 and compressed between the inner peripheral surface and theinner surface of the groove P872. According to this configuration,liquid-tight sealing is provided between the stem P87 and the windingstem pipe P86, so that a water-proof function is obtained. Incidentally,when the stem P87 is rotated, the rubber packing P91 rotates along withthe shaft P871 and slides in the circumferential direction while beingin close contact with the inner peripheral surface of the winding stempipe P86.

In the above description, as one example of the timepiece, a timepieceincluding a cover glass as the optical component according to theinvention has been described, however, the timepiece according to theinvention may be a timepiece including, for example, a component towhich the optical component according to the invention is applied as thecomponent other than the cover glass. For example, the rear lid or thelike may be one composed of the optical component according to theinvention. According to this, for example, the optical componentaccording to the invention is applied to a member closer to themovement, and therefore, the movement can be more effectively preventedfrom being electrically adversely affected, and thus, the reliability ofthe timepiece as a whole can be made particularly high. Further, theaesthetic appearance (aestheticity) of the timepiece as a whole can beimproved.

Further, in the above description, as one example of the timepiece, awristwatch (portable timepiece) as a solar radio timepiece has beendescribed, however, the invention can also be applied to other types oftimepieces such as portable timepieces other than wristwatches, tableclocks, and wall clocks in the same manner. Further, the invention canalso be applied to any timepieces such as solar timepieces other thansolar radio timepieces and radio timepieces other than solar radiotimepieces.

Hereinabove, preferred embodiments of the invention have been described,however, the invention is not limited to those described above.

For example, in the optical component and the timepiece according to theinvention, the configuration of each part can be replaced with anarbitrary configuration exhibiting a similar function, and also anarbitrary configuration can be added.

For example, the optical component may include a protective film or thelike in addition to the base material and the film (the film containingthe silica particles and the conductive transparent metal oxideparticles).

Further, the optical component according to the invention may include aplurality of films described above. For example, in the above-mentionedembodiment, a case where the film is provided on one surface side of thebase material has been described, however, the film may be provided onboth surface sides of the base material. Further, the optical componentmay have a configuration in which a plurality of films described aboveare stacked on one another through an intermediate layer.

Further, in the above-mentioned embodiment, a case where the opticalcomponent according to the invention is used as a constituent componentof a timepiece has been mainly described, however, the optical componentaccording to the invention is not limited to an optical component to beused as a constituent component of a timepiece, and may be an opticalcomponent to be applied to, for example, various electrical devicesincluding optical devices such as cameras (including video cameras,cameras mounted on cellular phones (including smart phones, PHS, etc.),and the like) and projectors, optical measurement devices such asmicroscopes, and the like, and also to eyeglasses, loupes, and the like.Further, the optical component according to the invention is not limitedto an optical component to be used in combination with another member,and may be an optical component to be used by itself alone.

Further, in the production of the optical component according to theinvention, other than the above-mentioned steps, according to need, apretreatment step, an intermediate treatment step, and a post-treatmentstep may be performed. For example, prior to the film formingcomposition application step, a step of performing UV irradiation,plasma irradiation, or the like on the surface of the base material maybe included. According to this, for example, the wettability of the filmforming composition on the base material can be made more favorable, andthe film having a desired condition (for example, a desired filmthickness) can be more favorably formed. Further, the adhesivenessbetween the base material and the film is made particularly excellent,and thus, the durability and reliability of the optical component can bemade particularly excellent.

Further, the optical component according to the invention is not limitedto those produced using the above-mentioned method. For example, in theabove-mentioned embodiment, a case where the film is formed by using afilm forming composition containing a dispersion medium in addition tosilica particles and conductive transparent metal oxide particles hasbeen described, however, for example, as the film forming composition, acomposition containing no dispersion medium may be used. Further, thefilm may be formed by, for example, mixing a composition containingsilica particles and a composition containing conductive transparentmetal oxide particles on a base material.

EXAMPLES

Next, specific examples of the invention will be described.

1. Production of Optical Component (Cover Glass) Example 1

By the method as described below, a cover glass as an optical componentwas produced.

First, a plate material (glass plate) composed of a sapphire glass wasprepared as a base material (the base material preparation step), and anecessary part was cut and polished. The base material obtained bycutting and polishing had a substantially disk shape and had a size of30 mm in diameter and 1 mm in thickness.

Subsequently, a UV irradiation treatment in which an ultraviolet raywith a wavelength of 248 nm was irradiated on the surface of the basematerial on the side where a film was going to be formed.

Subsequently, a film forming composition was applied onto the entiresurface of one side of the base material by a spray coating method (filmforming composition application step).

As the film forming composition, a composition obtained by mixing silicaparticles, tin oxide (SnO₂) particles (number-based average particlediameter: 2.0 nm) as conductive transparent metal oxide particles, andmethanol as a dispersion medium at a given ratio was used.

As the silica particles, silica particles which have a first localmaximum in the range of 1.5 nm or more and 2.5 nm or less (a firstrange), a second local maximum in the range of 3.5 nm or more and 4.5 nmor less (a second range), and a third local maximum in the range of 7.5nm or more and 8.5 nm or less (a third range), and a fourth localmaximum in the range of 5.5 nm or more and 6.5 nm or less (a fourthrange) in a number-based particle size distribution, and also have anumber-based average particle diameter of 2.6 nm were used.

Thereafter, the base material onto which the film forming compositionwas applied was left to stand in an environment at 1×10⁻⁴ Pa to removethe dispersion medium constituting the film forming composition(dispersion medium removal step), whereby the film was formed.

The average thickness of the formed film was 80 nm and the porosity was26% by volume. Further, the surface roughness Ra of the outer surface(the surface on an opposite side to the surface facing the basematerial) of the film was 1.3 nm.

Examples 2 to 6

Optical components (cover glasses) were produced in the same manner asin the above Example 1 except that the particle size distribution of thesilica particles constituting the film forming composition was changedas shown in Table 1, and the configuration of the film formingcomposition and the configurations of the respective parts of theoptical component were changed as shown in Table 2.

Example 7

An optical component (cover glass) was produced in the same manner as inthe above Example 1 except that prior to the film forming compositionapplication step, a foundation layer composed of SiO₂ was formed on thesurface of the base material (the surface on the side where the film wasgoing to be formed) (the foundation layer formation step).

The formation of the foundation layer was performed by vacuum vapordeposition. The thickness of the formed foundation layer was 15 nm.

Examples 8 and 9

Optical components (cover glasses) were produced in the same manner asin the above Example 7 except that the particle size distribution of thesilica particles constituting the film forming composition was changedas shown in Table 1, and the configuration of the film formingcomposition and the configurations of the respective parts of theoptical component were changed as shown in Table 2.

Comparative Example 1

An optical component (cover glass) was produced in the same manner as inthe above Example 2 except that the base material (the plate materialcomposed of a sapphire glass) was directly used as the optical componentwithout forming a film on the base material.

Comparative Example 2

First, a plate material (glass plate) composed of a sapphire glass wasprepared as a base material (the base material preparation step), and anecessary part was cut and polished. The base material obtained bycutting and polishing had a substantially disk shape and had a size of30 mm in diameter and 1 mm in thickness.

Subsequently, a UV irradiation treatment in which an ultraviolet raywith a wavelength of 248 nm was irradiated on the surface of the basematerial on the side where a film was going to be formed.

Thereafter, by using silicon as a target, sputtering was performed underthe following conditions, whereby a film composed of a high-refractiveindex layer and a low-refractive index layer was formed on one surfaceof the base material, whereby an optical component (cover glass) wasproduced. The specific stacking configuration of the film was as followsin the order from the side closer to the base material: SiO₂ (9nm)/SiN_(x) (37 nm)/SiO₂ (29 nm)/SiN_(x) (26 nm)/SiO₂ (53 nm)/SiN_(x)(22 nm)/SiO₂ (26 nm)/SiN_(x) (107 nm)/SiO₂ (81 nm).

Conditions for Formation of High-Refractive Index Layer:

-   Silicon Nitride (SiN_(x))    -   N₂ gas flow rate: 10.0 sccm    -   Ar gas flow rate: 10.0 sccm    -   Sputtering power: 2.0 kW

Conditions for Formation of Low-Refractive Index Layer:

-   Silicon Oxide (SiO₂)    -   O₂ gas flow rate: 10.0 sccm    -   Ar gas flow rate: 10.0 sccm    -   Sputtering power: 1.5 kW

The volume fraction of silicon nitride (SiN_(x)) from the outermostsurface of the film to the depth of 150 nm was 46%.

Comparative Example 3

An optical component (cover glass) was produced in the same manner as inthe above Example 2 except that as the film forming composition, acomposition containing no conductive transparent metal oxide particleswas used.

Comparative Example 4

An optical component (cover glass) was produced in the same manner as inthe above Example 2 except that as the film forming composition, acomposition containing no silica particles was used.

Comparative Example 5

An optical component (cover glass) was produced in the same manner as inthe above Example 2 except that an anionic surfactant was used as thefilm forming composition and the film was formed as a film composed of apolymeric organic material.

The particle size distributions of the silica particles constituting thefilm forming compositions used in the production of the opticalcomponents (cover glasses) of the respective Examples and ComparativeExamples are shown in Table 1, and the configurations of the filmforming compositions used in the production of the optical components(cover glasses) of the respective Examples and Comparative Examples andthe configurations of the respective parts of the optical components(cover glasses) of the respective Examples and Comparative Examples areshown in Table 2. Incidentally, in Tables 1 and 2, in the column of“average particle diameter”, the value of the number-based averageparticle diameter is shown. Further, in the above respective Examplesand Comparative Examples, the particle size distribution of theparticles was determined by laser diffractometry using a singlenanoparticle size analyzer IG-1000 (manufactured by ShimadzuCorporation). Further, the viscosities (viscosities in the film formingcomposition application step) of the film forming compositions used inthe above respective Examples and Comparative Examples as measuredaccording to JIS Z 8809 using a vibration-type viscometer were all inthe range of 3 mPa·s or more and 15 mPa·s or less.

TABLE 1 First range Second range Particle Ratio of silica Particle Ratioof silica Third range Presence or diameter of particles falling Presenceor diameter of particles falling Presence or absence of first localwithin first absence of second local within second absence of firstlocal maximum range second local maximum range third local maximum (nm)(vol %) maximum (nm) (vol %) maximum Example 1 presence 2.0 15 presence4.0 20 presence Example 2 absence — — presence 4.0 50 presence Example 3presence 2.0 15 presence 4.0 20 presence Example 4 presence 2.0 15presence 4.0 20 presence Example 5 presence 2.0 15 presence 4.0 20presence Example 6 presence 2.0 15 presence 4.0 20 presence Example 7presence 2.0 15 presence 4.0 20 presence Example 8 presence 2.0 15presence 4.0 20 presence Example 9 presence 2.0 15 presence 4.0 20presence Compar- — — — — — — — ative Example 1 Compar- — — — — — — —ative Example 2 Compar- absence — — presence 4.0 40 presence ativeExample 3 Compar- — — — — — — — ative Example 4 Compar- — — — — — — —ative Example 5 Third range Fourth range Particle Ratio of silicaParticle Ratio of silica diameter of particles falling Presence ordiameter of particles falling Average third local within third absenceof fourth local within fourth particle maximum range fourth localmaximum range diameter (nm) (vol %) maximum (nm) (vol %) (nm) Example 18.0 40 presence 6.0 25 2.6 Example 2 8.0 50 absence — — 4.3 Example 38.0 40 presence 6.0 25 2.6 Example 4 8.0 40 presence 6.0 25 2.6 Example5 8.0 40 presence 6.0 25 2.6 Example 6 8.0 40 presence 6.0 25 2.6Example 7 8.0 40 presence 6.0 25 2.6 Example 8 8.0 40 presence 6.0 252.6 Example 9 8.0 40 presence 6.0 25 2.6 Compar- — — — — — — ativeExample 1 Compar- — — — — — — ative Example 2 Compar- 8.0 60 absence — —4.6 ative Example 3 Compar- — — — — — — ative Example 4 Compar- — — — —— — ative Example 5

TABLE 2 Configuration of film forming composition Silica Conductivetransparent Dispersion Configuration of optical component particlesmetal oxide particles medium Base Foundation Film Con- Average Con- Con-material layer Con- Surface Poros- tent Constit- particle tent Constit-tent Constit- Constit- Thick- tent Thick- rough- ity (mass uent diameter(mass uent (mass uent uent ness Constituent (vol ness ness (vol %)material (nm) %) material %) material material (nm) material %) (nm) Ra(nm) %) Example 1 2.0 SnO₂ 2.0 0.1 meth- 97.9 Sapphire — — SiO₂particles/ 98.4/ 80 1.3 26 anol glass SnO₂ particles 1.6 Example 2 2.0SnO₂ 2.0 0.1 meth- 97.9 Sapphire — — SiO₂ particles/ 98.4/ 80 2.1 35anol glass SnO₂ particles 1.6 Example 3 2.0 SnO₂ 2.0 0.04 meth- 97.96Sapphire — — SiO₂ particles/ 99.7/ 80 1.3 26 anol glass SnO₂ particles0.3 Example 4 2.0 SnO₂ 2.0 0.5 meth- 97.5 Sapphire — — SiO₂ particles/92.6/ 80 1.3 25 anol glass SnO₂ particles 7.4 Example 5 2.0 SnO₂ 1.0 0.1meth- 97.9 Sapphire — — SiO₂ particles/ 98.4/ 80 1.2 25 anol glass SnO₂particles 1.6 Example 6 2.0 SnO₂ 5.0 0.1 meth- 97.9 Sapphire — — SiO₂particles/ 98.4/ 80 1.4 28 anol glass SnO₂ particles 1.6 Example 7 2.0SnO₂ 2.0 0.1 meth- 97.9 Sapphire SiO₂ 15 SiO₂ particles/ 98.4/ 80 1.3 26anol glass SnO₂ particles 1.6 Example 8 2.0 SnO₂ 2.0 0.1 meth- 97.9Sapphire SiO₂ 5 SiO₂ particles/ 99.5/ 80 1.3 26 anol glass SnO₂particles 0.5 Example 9 2.0 SnO₂ 2.0 0.1 meth- 97.9 Sapphire SiO₂ 25SiO₂ particles/ 99.5/ 80 1.1 26 anol glass SnO₂ particles 0.5 Compar- —— — — — — Sapphire — — SiO₂layer/ — 390 0.6 0 ative glass SiN_(x) layerExample 2 Compar- 2.0 — — — meth- 98.0 Sapphire — — SiO₂ particles 10080 1.0 14 ative anol glass Example 3 Compar- — SnO₂ 2.0 2.0 meth- 98.0Sapphire — — SnO₂ particles 100 80 1.0 14 ative anol glass Example 4Compar- — — — — — — Sapphire — — Anionic 100 10 0.5 — ative glasssurfactant Example 5

2. Evaluation of Antistatic Property

A probe was brought into contact with the surface on the side where thefilm was provided of each of the cover glasses produced in the aboverespective Examples and Comparative Examples, and the surface electricalresistance was measured by using a surface resistance meter (Hiresta-UPMCP-HT45 manufactured by Mitsubishi Chemical Corporation), andevaluation was performed according to the following criteria. It can besaid that as the surface electrical resistance is lower, the antistaticproperty is superior. The measurement was performed in an environment inwhich the temperature was 25° C. and the humidity was 55% RH.Incidentally, in the case of Comparative Example 1, the film was notprovided on both surfaces, and therefore, evaluation was performed forarbitrarily selected one surface (the same shall apply also to thefollowing evaluation items).

A: The surface electrical resistance is less than 1E+8Ω/□.

B: The surface electrical resistance is 1E+8Ω/□ or more and less than1E+9Ω/□.

C: The surface electrical resistance is 1E+9Ω/□ or more and less than1E+11Ω/□.

D: The surface electrical resistance is 1E+11Ω/□ or more and less than1E+15Ω/□.

E: The surface electrical resistance is 1E+15Ω/□ or more.

3. Evaluation of Reflectance

With respect to each of the cover glasses produced in the aboverespective Examples and Comparative Examples, the light reflectance fromthe cover glass was measured from the surface on the opposite side tothe surface on which the film was provided of the base material using areflectometer USPM manufactured by Olympus Corporation, and evaluationwas performed according to the following criteria.

A: The light reflectance is less than 0.3%.

B: The light reflectance is 0.3% or more and less than 0.5%.

C: The light reflectance is 0.5% or more and less than 1.0%.

D: The light reflectance is 1.0% or more and less than 4.0%.

E: The light reflectance is 4.0% or more.

4. Evaluation of Antifogging Property

The antifogging property evaluation index when saturated water vapor wassprayed onto the surface on the side where the film was provided of eachof the cover glasses produced in the above respective Examples andComparative Examples was obtained by using an antifogging propertyevaluation device (AFA-1 manufactured by Kyowa Interface Science Co.,Ltd.), and evaluation was performed according to the following criteria.It can be said that as the antifogging property evaluation index islower, the antifogging property is superior.

A: The antifogging property evaluation index is less than 3.

B: The antifogging property evaluation index is 3 or more and less than6.

C: The antifogging property evaluation index is 6 or more and less than10.

D: The antifogging property evaluation index is 10 or more and less than20.

E: The antifogging property evaluation index is 20 or more.

5. Evaluation of Adhesiveness

Five horizontal cut lines at 2 mm intervals and five vertical cut linesat 2 mm intervals were provided on the surface to be evaluated with acutter, and an adhesive tape (CT-18 manufactured by Nichiban Co., Ltd.)was adhered thereto, and thereafter, the adhesive tape was peeled off ata stroke. Then, it was confirmed whether or not peeling occurred on thesurface to be evaluated by visual observation, and evaluation wasperformed according to the following criteria.

A: No film peeling is observed.

B: The percentage of the area where film peeling occurred is less than5%.

C: The percentage of the area where film peeling occurred is 5% or moreand less than 20%.

D: The percentage of the area where film peeling occurred is 20% or moreand less than 50%.

E: The percentage of the area where film peeling occurred is 50% ormore.

6. Evaluation of Abrasion Resistance

An abrasion resistance test using silbon paper as a counter paper wasperformed according to JIS K 5701 for the surface on the side where thefilm was provided of each of the cover glasses produced in the aboverespective Examples and Comparative Examples. Then, the cover glassafter the abrasion resistance test was visually observed, and evaluationwas performed according to the following criteria.

A: No scratches by rubbing occur.

B: Almost no scratches by rubbing occur.

C: Scratches by rubbing slightly occur.

D: Scratches by rubbing clearly occur.

E: Scratches by rubbing remarkably occur.

7. Production of Timepiece

By using each of the cover glasses produced in the above respectiveExamples and Comparative Examples, wristwatches as shown in FIG. 4 wereproduced. At this time, the surface on the side where the film wasprovided of the cover glass was disposed facing the inner surface side(a side facing the dial plate and the like).

8. Evaluation of Visibility of Dial Plate of Timepiece

With respect to each of the timepieces produced in the above respectiveExamples and Comparative Examples, the dial plate and the like wereobserved through the cover glass, and the visibility at that time wasevaluated according to the following criteria.

A: The visibility of the dial plate and the like is very high.

B: The visibility of the dial plate and the like is high.

C: The visibility of the dial plate and the like is within theacceptable range.

D: The visibility of the dial plate and the like is somewhat low.

E: The visibility of the dial plate and the like is very low.

These results are shown in Table 3.

TABLE 3 Antistatic Antifogging Abrasion Visibility of propertyReflectance property Adhesiveness resistance dial plate Example 1 A A AB A A Example 2 A B C B A B Example 3 C A A B A A Example 4 A B A B A BExample 5 A A A B A A Example 6 A B A B A B Example 7 A A A A A AExample 8 A A A B A A Example 9 A B A A A B Compar- E E E — A E ativeExample 1 Compar- E B E A A A ative Example 2 Compar- D C D C B C ativeExample 3 Compar- B E D C C E ative Example 4 Compar- E E A D D E ativeExample 5

As apparent from Table 3, according to the invention, the opticalcomponent had an excellent antistatic function, and also had excellentantireflection function, antifogging property, and abrasion resistance.In particular, an excellent effect as described above was obtained witha simple structure. Further, the timepieces including the opticalcomponent had high visibility of the dial plate and the like, and theaesthetic appearance (aestheticity) of the timepiece as a whole wasexcellent. In addition, according to the invention, the opticalcomponent could be produced with high productivity. On the other hand,in the case of Comparative Examples, satisfactory results were notobtained. In particular, in the case of Comparative Example 2 in which afilm having a complicated structure such that many layers were stackedwas formed by a chemical vapor deposition the productivity of theoptical component was particularly low.

When timepieces were produced in the same manner as in the aboverespective Examples and Comparative Examples except that in addition tothe cover glass, also the rear lid was configured in the same manner asdescribed above, the same results as described above were obtained, andin the timepieces to which the optical component according to theinvention was applied (timepieces according to the invention), theaesthetic appearance (aestheticity) could be made particularlyexcellent.

When cover glasses (optical components) and timepieces were produced inthe same manner as described above except that the application of thefilm forming composition was performed by a roll coating method or aspin coating method and the evaluation was performed in the same manneras described above, the same results as described above were obtained.

The entire disclosure of Japanese Patent Application No. 2014-244846,filed Dec. 3, 2014 is expressly incorporated by reference herein.

What is claimed is:
 1. An optical component comprising: a base material;and a film containing silica particles and conductive transparent metaloxide particles.
 2. The optical component according to claim 1, whereinthe volume resistivity of the constituent material of the conductivetransparent metal oxide particles is 100 Ωcm or less.
 3. The opticalcomponent according to claim 1, wherein the conductive transparent metaloxide particles are composed of SnO₂.
 4. The optical component accordingto claim 1, wherein the number-based average particle diameter of theconductive transparent metal oxide particles is 0.8 nm or more and 5.0nm or less.
 5. The optical component according to claim 1, wherein thenumber-based average particle diameter of the silica particles is 0.5 nmor more and 4.0 nm or less.
 6. The optical component according to claim1, wherein when the number-based average particle diameter of the silicaparticles is represented by Ds (nm) and the number-based averageparticle diameter of the conductive transparent metal oxide particles isrepresented by Dc (nm), the following relationship is satisfied:0.1≦Dc/Ds≦0.6.
 7. The optical component according to claim 1, whereinwhen the content of the silica particles in the film is represented byXs (vol %) and the content of the conductive transparent metal oxideparticles in the film is represented by Xc (vol %), the followingrelationship is satisfied: 0.003≦Xc/Xs≦0.12.
 8. The optical componentaccording to claim 1, wherein the thickness of the film is 50 nm or moreand 120 nm or less.
 9. The optical component according to claim 1,wherein the base material is composed of a material containing at leastone member selected from the group consisting of a silicate glass, asapphire glass, and a plastic.
 10. The optical component according toclaim 1, wherein the optical component is a cover glass for a timepiece.11. A timepiece comprising the optical component according to claim 1.12. A timepiece comprising the optical component according to claim 2.13. A timepiece comprising the optical component according to claim 3.14. A timepiece comprising the optical component according to claim 4.15. A timepiece comprising the optical component according to claim 5.16. A timepiece comprising the optical component according to claim 6.17. A timepiece comprising the optical component according to claim 7.18. A timepiece comprising the optical component according to claim 8.19. A timepiece comprising the optical component according to claim 9.20. A timepiece comprising the optical component according to claim 10.